Explosion-proof switch



June 3, 1958 F. WEISSER 2,837,617

EXPLCSION-PROOF SWITCH Filed Sept. 6, i955 2 Sheets-Sheet 1 INVENTOP June 3, 1958 F. WEISSER EXPLOSION-PROOF SWITCH 2 Sheets-Sheet 2 Filed Sept. 6, 1955 lNVENTO United EXPLosIoN-Pnoor swrrcn Application September 6, 1955, Serial No. 532,558

2 Claims. (Cl. 200-168) The invention relates to an arrangement for the enclosure of electrical switches, and particularly to an arrangement for rendering such switches explosion-proof.

The primary object of the invention is to produce a switch arrangement in which two parts of a casing enclosing the switch are so connected that there is no tendency for them to work apart during normal operation.

Another object of the invention is to provide a connecting arrangement for the casing parts which can be readily engaged or released to allow access to the switch.

A further object of the invention is to provide a connection in which neither bolts nor rivets are used. Where rivets are used for connecting two casing parts, the joint is likely to be loose unless the heads are set with care, it is difiicult to open the casing for repairing the switch, and the strain on the casing may cause cracking at the points of the rivet heads. When screws are used, the assembly is relatively expensive because screws of high quality are required, and in addition these screws are likely to work loose. There is also the danger that they will be damaged during the assembling and disassembling of the casing for repair.

According to the present arrangement, the two casing parts are clamped together in such a way as to prevent the danger of escape of the explosion while the assembly is inexpensive and economical.

Further objects and advantages of the invention will appear more fully from the following description, particularly when taken in conjunction with the accompanying drawings which form a part hereof.

In the drawings:

Fig. 1 shows in top plan view a switch casing embodying the invention with the assembly cover omitted;

Fig. 2 is a cross-section on the line Il-ll of Fig. 1;

Figs. 3 and 4 are views similar to Figs. 1 and 2 respectively of a modified form of the invention, Fig. 4 being a section on line IV-IV of Fig. 3.

In the form of Figs. 1 and 2, the switch contacts are enclosed in a casing formed of upper part 1 and lower ates Patent 2,837,617 Patented June 3, 1958 part 2, the contacts being connected to terminals on the outside of these parts. These parts have closely fitting mating faces. The outer corners of the parts are sloped along two parallel sides at 4 and 5, and are arranged to fit into a metallic clamping member 6 of U-shape having inwardly turned free edges. These free edges and the corners of the U-shaped clamp are provided with sloping shoulders, these shoulders being slidable over the sloped corners 4, 5 of the casing parts.

The switch is enclosed in an outer casing 7, and is operated by a push button 3.

In the form of Figs. 3 and 4, the use of a clamping member separate from the casing is avoided. In this form, outer casing 7' has inwardly directed ribs 9 with inclined lower faces against which surfaces 4 press, the lower part 2 engaging an upward central projection 8 of easing 7'. Strips of metal having slits at each end may be positioned between shoulder 4 and rib 9, the ends 10 of these strips being oppositely bent so as to prevent displacement of the casing along the ribs 9.

In either form, the clamping pieces fit the casing parts tightly and resist separation of such parts by an explosion.

The parts are inexpensive and the whole arrangement is quite economical.

The clamps may be of any suitable material, such as metal or plastic.

It is preferable that the surfaces engaging shoulders 4, 5 be slightly convergent so as to exert a wedging action when the casing parts are pushed between the clamping surfaces. 1

While I have described herein some embodiments of my invention, I wish it to be understood that I do not intend to limit myself thereby except within the scope of the claims hereto or hereinafter appended.

I claim: i

1. A switch casing comprising a box having ribs along its side walls, said ribs having sloping lower surfaces, and two mating switch-enclosing parts, one part being slidable on the bottom of the box and the other part having sloping corners slidably engaging said sloping surfaces to clamp the parts in the box.

2. A switch casing comprising a holding member having a bottom wall and side walls and inwardly directed portions on opposite side walls thereof, said portions having sloping lower surfaces, and two mating switch-enclosing parts, said member having means associated with the bottom and side walls slidably engaging one of said parts, the other part having sloping corners slidably engaging said sloping surfaces to clamp the parts in the member. l

References Cited in the file of this patent UNITED STATES PATENTS 2,723,327 Gilbert Nov. 8, 1955 

